Locking nut and bolt system with enhanced locking

ABSTRACT

The locking nut and bolt system includes an elongated locking unit, mounted in a nut and operative with a specially configured groove bolt. The locking unit includes a plurality of at least three tines, asymmetrically located, which protrude tangentially and generally radially inward. The tines are radially asymmetrically disposed such that when a respective tine latches into a corresponding groove, asynchronous locking operation is achieved. When the tine is engaged in the groove, counter-rotational movement (loosening) is prohibited. In another embodiment, the locking unit has different sized edge cut-outs prohibiting the locking insert from rotating within the nut. The locking unit may also include a longitudinal split and a key and a keyway. A manufacturing process is also disclosed.

This is a divisional patent application based upon and claiming thebenefit of U.S. patent application Ser. No. 10/978,127 filed Oct. 29,2004, now U.S. Pat. No. 7,189,044.

The present invention relates to a locking nut and bolt system and alocking nut insert utilized in connection with a specially configuredbolt to provide enhanced locking or resistance to counter-rotativemotion. A manufacturing process for the locking unit insert is alsodisclosed.

BACKGROUND OF THE INVENTION

Nut and bolt systems typically compress elements therebetween and mountone component to another component. Sometimes, the mounted assembly issubjected to vibrations which cause counter-rotative torque on the nutand bolt such that the nut loosens on the bolt and the componentsforming the assembly become loose and unattached. It is helpful to havea locking nut and bolt system and a locking nut insert (operable inconjunction with a specially configured bolt) which prohibitscounter-rotative movement and therefore maintains the components in amounted or fixed assembly.

Various locking nut and bolt systems are disclosed in U.S. Pat. No.6,010,289 to DiStasio; U.S. Pat. No. RE35,937 to DiStasio; and U.S. Pat.No. 5,951,224 to DiStasio. The content and specification of U.S. Pat.No. 6,010,289 is incorporated herein by reference thereto. U.S. Pat. No.307,722 to Klemroth discloses bolts having grooves thereon. Thefollowing patents disclose the use of bolts carrying grooves and one ormore locking tines operative with the grooves on the bolts to prevent orlimit loosening of the nut and bolt: U.S. Pat. No. 1,136,310 to Burnett;U.S. Pat. No. 1,226,143 to Stubblefield; U.S. Pat. No. 2,521,257 toSample; and U.S. Pat. No. 5,238,342 to Stencel.

OBJECTS OF THE INVENTION

It is an object of the present invention to provide a locking nut andbolt system (and a locking nut insert) wherein the locking nut insertcarries a plurality of locking tines which are not radially symmetricalto each other, thereby enhancing the locking characteristic of thelocking nut and bolt system.

It is a further object of the present invention to provide a locking nutand bolt system (and a locking nut insert) wherein the insert is betterfixed within the nut due to half-moon cut-out edge segments.

It is a further object of the present invention to provide a locking nutand bolt system with enhanced locking features wherein the lockingaction of a respective tine in a corresponding bolt groove isasynchronous with respect to other tines and other grooves on thelocking unit insert and the bolt, respectively.

It is a further object of the present invention to provide a locking nutinsert which is longitudinally split to enhance handling andmanufacturing characteristics of the locking unit insert.

SUMMARY OF THE INVENTION

The locking nut and bolt system includes a specially configured boltoperative with an elongated locking unit, which locking unit is mountedin a recess defined on an end face of a nut. The bolt carries aplurality of notches on its threads, which notches are in apredetermined pattern generally longitudinal (which may include spiralor diagonal configurations). The elongated locking unit includes aplurality of at least three tines (in one embodiment) which protrudetangentially and generally radially inward towards the axial centerlineof the bolt. The tines, in one embodiment, are radially asymmetricallydisposed about the axial centerline such that when a respective tinelatches into a corresponding groove, asynchronous locking operation isachieved with respect to the remaining tines and grooves. When the tinefalls within the groove, counter-rotational movement (suggesting aloosening of the nut and bolt) is prohibited due to abutment of thedistal tine end against the lock face of the groove. In anotherembodiment, the elongated locking unit has half-moon cut-out edgesegments that are swaged to the nut thereby prohibiting the locking unitinsert from rotating within the nut recess. Further enhancements includeconfiguring the locking unit as one of an elongated cylinder or anelongated polygonal unit having five or more sides. The elongatedlocking unit also includes a longitudinal split which enhances handlingand manufacture of the locking unit insert. The split may be formed byinterleaved surfaces which define opposing sides of the longitudinalsplit. A key and a keyway may also be formed on the interleavedsurfaces.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects and advantages of the present invention can be found inthe description of the preferred embodiments which follows and in theaccompanying drawings which show:

FIG. 1 a diagrammatically illustrates a locking nut and bolt system withthe bolt having a straight longitudinal groove thereon;

FIG. 1 b diagrammatically shows a cross-sectional view of the groovedbolt;

FIG. 2 diagrammatically illustrates a grooved bolt with a spiral orsomewhat diagonally positioned groove or notched region;

FIGS. 3 a and 3 b diagrammatically illustrate a perspective view of thelocking unit insert and a nut thread axial end view of the lockinginsert, respectively;

FIG. 4 diagrammatically illustrates a plan view of the locking unitinsert;

FIG. 5 diagrammatically illustrates a locking unit insert cooperatingwith a grooved bolt (CR denoting counter-rotative or loosening force) ordirection;

FIG. 6 diagrammatically illustrates a detail view of a tine falling intoa notch in the notched or grooved bolt;

FIGS. 7 a and 7 b diagrammatically illustrate a portion of the nut, nutrecess and a wall segment of the locking nut insert as well as the swagemount of the insert on the nut;

FIG. 8 diagrammatically illustrates a perspective view of the lockingunit insert placed in a nut recess prior to swaging; and

FIGS. 9 a and 9 b diagrammatically illustrate polygonal locking insertsrepresenting embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to a locking nut and bolt system(including a locking nut insert) with enhanced locking capabilities. Amanufacturing process is also described for the locking unit insert.

FIG. 1 a diagrammatically illustrates a bolt 20 having a bolt head 22and a bolt stem 24. Bolt 20 includes threads which include thread crests26 and thread troughs 28. Nut 40 includes a plurality of threads whichare complementary to the thread system 26, 28 on bolt stem 24. Axialcenterline 60 is related to the axial centerline of the bolt 20 as wellas nut 40. Axial thread end 31 is also shown in FIG. 1 a. Reference toan outboard position of the locking nut insert (not shown in FIG. 1 a)refers to items closer to axial thread end 31. The term “inboard” refersto items closer to bolt head 22.

FIG. 1 b diagrammatically shows a cross-sectional view of grooved bolt20. Particularly, thread crest 26 includes a generally longitudinalgroove 34 thereat. Groove 34 includes a leading surface 38 and a lockingsurface 36. Groove 34, in a preferred embodiment, does not exceed thethread trough or root 32 of the thread system 26, 28. This featurereduces stress fractures which may occur if the groove or notch isdeeper than root 32.

FIG. 2 diagrammatically illustrates a diagonal or a spiral groove 43 onbolt thread 45. Axial centerline D′-D″ is also shown in FIG. 2. Itshould be noted that bolt 20 may contain a plurality of grooves as shownin connection with bolt 20 in FIG. 5. Further, these grooves aregenerally longitudinally disposed in a predetermined pattern, whichpattern may be limited to a portion of the longitudinal aspect of bolt20. In FIG. 1 a, groove 34 does not extend the entire thread portion 26,28 of bolt 20. In other embodiments, the groove may extend the entirethread. Further, adjacent grooves formed on thread crests are generallylongitudinally adjacent each other even if slightly arcuately displacedwith respect to each other as shown in conjunction with the spiralgroove 43 in FIG. 2.

FIGS. 3 a and 3 b diagrammatically illustrate a perspective view and athread end axial view of locking unit insert 50. Locking unit insert 50is generally cylindrically shaped (but see FIG. 11 a for a differentshape) and includes a plurality of at least three tines 52 which areprotruding tangentially and generally radially inward towards the axialcenterline of the locking nut and bolt system. Tine 52 includes a distaltine end 54 and a proximal base region 56, which base is attached to orformed by tine wall 58. Similar numbers designate similar itemsthroughout the figures.

As shown in FIG. 4, a plan view of locking unit insert 50, tines 52 areformed by cutting or stamping a U-shape on a strip of metal. Althoughmetal is used in the preferred embodiment, other materials may beemployed. In the preferred embodiment, locking unit insert 50 includes alongitudinal split 62 extending the axial length of unit 50. In afurther enhancement, split 62 is formed by opposing sides 64, 66. In anenhancement, opposing side 64 forms a key which fits within oppositeside 66 forming a keyway. In this manner, key 64 aligns with keyway 66to form split 62. Also, the locking unit insert can be slightlycompressed thereby reducing its diameter to facilitate insertion of thelocking unit into a recess in the nut end face discussed later inconjunction with FIG. 10. In FIG. 3 b, split 62 is seen as split portion62 b.

To manufacture locking insert 50, a flat plate is cut per the plan viewin FIG. 4 including stamp-cut tines 52 and key and keyway edge surfaces64, 66. Then the plate is rolled such that key 64 is folded into keyway66. See FIG. 3 a. Also, tines 52 are radially inwardly compressed orpunched upward from the plate to form the radial tines. The order ofplate rolling and punching tines is not critical.

To ensure that the locking unit 50 does not rotate within nut recess,the locking unit on outboard edge 68 includes at least two cut-outs 70,72. These cut-outs are sometimes called herein different sized half-mooncut-out edge segments. Also, cut-outs may be cavities formed by anycutting or forming process. Each cut-out 70, 72 has a different arcuatelength a, b, which further enhances handling of the locking unit insert50. In addition, cut-outs 70, 72 are placed intermediate the variouspositions of locking tines 52. The intermediate position of the mountinglock cut-outs 70, 72 reduces stress and fatigue in the insert duringuse.

One aspect of the present invention is that the locking tines areradially asymmetrically disposed on locking unit 50. In other words,distance E between the left side tines 52 is different than distance Fbetween the intermediate tine and the right side tine 52.

FIG. 5 shows the radially asymmetrical configuration of tines 52 a, 52b, and 52 c. Further, the locking nature of tine 52 a is asynchronouswith respect to the same locking operations of tine 52 b and tine 52 c.In other words, when tine 52 a locks, tines 52 b and 52 c are riding onthread crests or lands 35 b and 35 c. In a similar manner, when tine 52b locks in groove 34 b, tine 52 c is riding on crest or land 35 c. Atthat time during counter-rotation CR movement of bolt 21 with respect tolocking insert 50, tine 52 a is on the adjacent left land. Currenttesting of the locking nut and bolt system indicates that a single tineis sufficient to prevent counter-rotative movement of bolt 21 withrespect to locking nut insert 50. Therefore, radially asymmetricdisposition of the tines with respect to each other about the axialcenterline is adequate to lock the nut and bolt. Radially asymmetricaldisposition is achieved if the arcuate distance between tines 52 a-52 bis different than the arcuate distance between tines 52 b and 52 c. Inone working embodiment, the arcuate distance between tines 52 a-52 b isthe same as the arcuate distance between tines 52 a-52 c, that being106.7 degrees for a ⅜ inch bolt. However, since the arcuate distance 52b-52 c is not the same as distance 52 a-52 b (or 52 a-52 c),asymmetrical positioning is achieved, resulting in the asynchronouslocking of the plurality of tines in the plurality of notches. The tinesare not symmetrically located about the axial centerline because 52 b-52c is a different arcuate distance than 52 a-52 b or 52 a-52 c. Otherasymmetrical positions may be utilized.

FIG. 6 diagrammatically shows that tine 52 a is operative in a lockingposition in groove 34 a. By altering the number of tines and the numberof grooves and providing radially asymmetric placement of the tinesabout the axial centerline, locking action is achieved with a minimalrotational movement in the counter-rotational direction CR (loosening orunscrewing direction). Further, a calculation can establish the maximumunlock arcuate movement necessary before any particular tine falls andlocks into a corresponding locking face 36 of a groove. This maximumunlock arcuate distance translates into the maximum seat torque loadlost due to counter-rotative movement. Asymmetrical tine placementreduces seat torque load losses. Also, alternatively, asynchronouslocking of one tine with respect to others reduces seat torque loadlosses.

A plurality of tines greater than three may be utilized in radiallyasymmetric positioning. A plurality of grooves or notches on the boltthread may also be utilized.

FIGS. 7 a and 7 b diagrammatically show a cross-section of nut 80 havinga nut end face 82. FIG. 9A shows wall segment 81 of locking nut insert50. Nut end face 82 has a small build up area 84. Build up area 84 issubsequently crushed or swaged to capture wall segment 81. The swagedarea 84 b is shown in FIG. 7 b.

FIG. 8 diagrammatically shows locking nut insert 50 placed within recess86 of nut 80. Build up area 84 has not been swaged upon half-mooncut-out edge segment 70 of locking nut insert 50. As is known in theart, nut threads 81 are complementary to bolt threads 26, 28 in FIG. 1a. The utilization of outboard cut-out edge segment 70 enables thelocking nut insert 50 to be firmly locked or swaged or mounted in nut80. The locking of the locking nut insert 50 in nut 80 is important inthat the insert should not rotate when the tine falls within thecorresponding groove during the prohibition of counter-rotationalmovement. By utilizing an inboard cut-out edge segment (not shown),additional locking forces are established for the locking nut insert.

FIGS. 9 a and 9 b diagrammatically show locking unit inserts 90 and 92.These inserts have longitudinal splits 93. Locking inserts 90, 92 areshaped as polygons having at least five or more sides. The polygonalshapes enhance handling of the locking nut inserts and insertion intonut recesses 86.

In FIG. 9 b, inboard edge 94 has been crimped inward to form a radialledge. This radial ledge may also enhance handling of the locking nutinsert during manufacture. Of course, the locking nut insert ismechanically handled by machines and inserted into nut recess 86. Byutilizing radial ledge 94 and detecting radial ledge 94, the lockinginsert 92 can be properly placed into nut recess 86. The utilization ofdifferent sized cut-outs 70, 72 shown in FIG. 4 also enhances handlingsince the machines can detect the edge 68 having cut-outs 70, 72 ascompared with inboard edge which is opposite edge 68. Proper insertionof the locking nut inserts into nut recess 86 is important. If thelocking nut inserts are placed in nut recess 86 “upside down,” lockingis not achieved in the counter-rotational movement direction.

The claims appended hereto are meant to cover modifications and changeswithin the scope and spirit of the present invention.

1. A method of manufacturing a locking nut insert comprising: stamping aplate as an elongated strip to form a plurality of at least threetine-tabs which are not symmetrically spaced on said elongated strip andforming interleaving forward and rear edges; rolling said elongatedstrip to interlock said forward and rear edges thereby forming acylindrical locking nut insert with a longitudinal split, said splitformed by said forward and rear edges; punching or compressing saidtine-tabs from said plate thereby forming an elongated locking unit witha plurality of tines protruding tangentially and generally radiallyinward toward an axial centerline of said elongated locking unit; saidplurality of at least three tines being radially asymmetrically disposedabout said axial centerline, the asymmetric radial disposition of saidat least three tines creating a different arcuate space between at leasttwo of said three tines, each tine having a distal tine end adapted tolatch, said asymmetric disposition of said plurality of tines resultingin asynchronous locking of said plurality of tines.
 2. A method ofmanufacturing a locking nut insert as claimed in claim 1 includingforming at least one top cavity on an edge.
 3. A method of manufacturinga locking nut insert as in claim 1 including forming one of an elongatedcylinder and an elongated polygonal unit having five or more sides witha having longitudinal split thereat.
 4. A method of manufacturing alocking nut insert as in claim 3 including forming a key and a keyway atthe interleaved surfaces.